As users impose an increasingly high requirement on network bandwidth, a conventional copper wire bandwidth access system cannot meet the increasingly high user requirement. A WDM-PON technology draws much attention because of its advantages such as a huge broadband capacity and information security that is similar to that of point-to-point communication.
In a WDM-PON system, a node on a user end uses an array waveguide grating (AWG) or a waveguide grating router (WGR) as an optical multiplexer, where wavelengths of all output ports of the AWG or the WGR are different from each other. Optical network units (ONUs) connected to the ports of the AWG or the WGR include two kinds of modules a colored optical module and a colorless optical module.
It is required that an optical signal can be received only when a wavelength of a laser in the ONU is the same as a wavelength of a port of the AWG or the WGR that is connected to the ONU when an ONU is a colored optical module. Therefore, wavelengths of lasers in the ONUs connected to the ports of the AWG or the WGR are different from each other, and the ONUs of the ports cannot be used universally, which leads to a problem such as ONU access difficulty.
To ensure that the ONUs connected to the ports of the AWG or the WGR are unrelated to the wavelengths of the ports connected to the ONUs, and resolve the problem such as ONU access difficulty, a colorless optical module is used as an ONU. An emission wavelength of a laser in the colorless optical module may be automatically adjusted to a wavelength of a port of the AWG or the WGR that is connected to the colorless optical module such that the colorless optical module can be plugged and played on any port.
A stable laser signal can be generated only when a gain of a laser in an ONU is greater than a round-trip loss of an optical signal and when the ONU is a colorless optical module. Therefore, to ensure that the WDM-PON system is in a lasing state, an emission parameter of the laser needs to be adjusted such that power of output light of the system meets an actual application requirement. Currently, in the prior art, the emission parameter of the laser is mainly adjusted using a backlight detection technology, where optical power of backlight of the laser is detected, and the emission parameter of the laser is adjusted according to the optical power of the backlight, to change the power of the output light of the system, thereby implementing adjustment on the power of the output light of the WDM-PON system. However, the backlight detection technology can only directly reflect the power of the output light of the laser, but cannot effectively reflect the power of the output light of the WDM-PON system, leading to low precision when output power of the system is adjusted.